
(FPCore (u v) :precision binary32 (+ 1.0 (* v (log (+ u (* (- 1.0 u) (exp (/ -2.0 v))))))))
float code(float u, float v) {
return 1.0f + (v * logf((u + ((1.0f - u) * expf((-2.0f / v))))));
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = 1.0e0 + (v * log((u + ((1.0e0 - u) * exp(((-2.0e0) / v))))))
end function
function code(u, v) return Float32(Float32(1.0) + Float32(v * log(Float32(u + Float32(Float32(Float32(1.0) - u) * exp(Float32(Float32(-2.0) / v))))))) end
function tmp = code(u, v) tmp = single(1.0) + (v * log((u + ((single(1.0) - u) * exp((single(-2.0) / v)))))); end
\begin{array}{l}
\\
1 + v \cdot \log \left(u + \left(1 - u\right) \cdot e^{\frac{-2}{v}}\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (u v) :precision binary32 (+ 1.0 (* v (log (+ u (* (- 1.0 u) (exp (/ -2.0 v))))))))
float code(float u, float v) {
return 1.0f + (v * logf((u + ((1.0f - u) * expf((-2.0f / v))))));
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = 1.0e0 + (v * log((u + ((1.0e0 - u) * exp(((-2.0e0) / v))))))
end function
function code(u, v) return Float32(Float32(1.0) + Float32(v * log(Float32(u + Float32(Float32(Float32(1.0) - u) * exp(Float32(Float32(-2.0) / v))))))) end
function tmp = code(u, v) tmp = single(1.0) + (v * log((u + ((single(1.0) - u) * exp((single(-2.0) / v)))))); end
\begin{array}{l}
\\
1 + v \cdot \log \left(u + \left(1 - u\right) \cdot e^{\frac{-2}{v}}\right)
\end{array}
(FPCore (u v) :precision binary32 (+ (* (log (+ (* (pow (exp (/ -1.0 v)) 2.0) (- 1.0 u)) u)) v) 1.0))
float code(float u, float v) {
return (logf(((powf(expf((-1.0f / v)), 2.0f) * (1.0f - u)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((((exp(((-1.0e0) / v)) ** 2.0e0) * (1.0e0 - u)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32((exp(Float32(Float32(-1.0) / v)) ^ Float32(2.0)) * Float32(Float32(1.0) - u)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((((exp((single(-1.0) / v)) ^ single(2.0)) * (single(1.0) - u)) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left({\left(e^{\frac{-1}{v}}\right)}^{2} \cdot \left(1 - u\right) + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
lift-/.f32N/A
clear-numN/A
frac-2negN/A
associate-/r/N/A
exp-prodN/A
lower-pow.f32N/A
lower-exp.f32N/A
neg-mul-1N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Final simplification99.5%
(FPCore (u v)
:precision binary32
(if (<= (* (log (+ (* (exp (/ -2.0 v)) (- 1.0 u)) u)) v) -1.0)
(+
(fma
(* (fma -24.0 u 8.0) u)
(/ 0.16666666666666666 (* v v))
(* (* u u) (- (/ (+ (/ -2.0 u) (+ (/ 2.0 v) 2.0)) u) (/ 2.0 v))))
1.0)
1.0))
float code(float u, float v) {
float tmp;
if ((logf(((expf((-2.0f / v)) * (1.0f - u)) + u)) * v) <= -1.0f) {
tmp = fmaf((fmaf(-24.0f, u, 8.0f) * u), (0.16666666666666666f / (v * v)), ((u * u) * ((((-2.0f / u) + ((2.0f / v) + 2.0f)) / u) - (2.0f / v)))) + 1.0f;
} else {
tmp = 1.0f;
}
return tmp;
}
function code(u, v) tmp = Float32(0.0) if (Float32(log(Float32(Float32(exp(Float32(Float32(-2.0) / v)) * Float32(Float32(1.0) - u)) + u)) * v) <= Float32(-1.0)) tmp = Float32(fma(Float32(fma(Float32(-24.0), u, Float32(8.0)) * u), Float32(Float32(0.16666666666666666) / Float32(v * v)), Float32(Float32(u * u) * Float32(Float32(Float32(Float32(Float32(-2.0) / u) + Float32(Float32(Float32(2.0) / v) + Float32(2.0))) / u) - Float32(Float32(2.0) / v)))) + Float32(1.0)); else tmp = Float32(1.0); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\log \left(e^{\frac{-2}{v}} \cdot \left(1 - u\right) + u\right) \cdot v \leq -1:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-24, u, 8\right) \cdot u, \frac{0.16666666666666666}{v \cdot v}, \left(u \cdot u\right) \cdot \left(\frac{\frac{-2}{u} + \left(\frac{2}{v} + 2\right)}{u} - \frac{2}{v}\right)\right) + 1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if (*.f32 v (log.f32 (+.f32 u (*.f32 (-.f32 #s(literal 1 binary32) u) (exp.f32 (/.f32 #s(literal -2 binary32) v)))))) < -1Initial program 92.6%
Taylor expanded in v around inf
+-commutativeN/A
associate-+l+N/A
*-commutativeN/A
+-commutativeN/A
lower-fma.f32N/A
Applied rewrites5.3%
Applied rewrites5.6%
Taylor expanded in u around 0
Applied rewrites52.9%
Taylor expanded in u around -inf
Applied rewrites59.0%
if -1 < (*.f32 v (log.f32 (+.f32 u (*.f32 (-.f32 #s(literal 1 binary32) u) (exp.f32 (/.f32 #s(literal -2 binary32) v)))))) Initial program 100.0%
Taylor expanded in v around 0
Applied rewrites90.9%
Final simplification85.4%
(FPCore (u v) :precision binary32 (+ (* (log (+ (* (exp (/ -2.0 v)) (- 1.0 u)) u)) v) 1.0))
float code(float u, float v) {
return (logf(((expf((-2.0f / v)) * (1.0f - u)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log(((exp(((-2.0e0) / v)) * (1.0e0 - u)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32(exp(Float32(Float32(-2.0) / v)) * Float32(Float32(1.0) - u)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log(((exp((single(-2.0) / v)) * (single(1.0) - u)) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(e^{\frac{-2}{v}} \cdot \left(1 - u\right) + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
Final simplification99.5%
(FPCore (u v) :precision binary32 (+ (* (log (+ (exp (/ -2.0 v)) u)) v) 1.0))
float code(float u, float v) {
return (logf((expf((-2.0f / v)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((exp(((-2.0e0) / v)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(exp(Float32(Float32(-2.0) / v)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((exp((single(-2.0) / v)) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(e^{\frac{-2}{v}} + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
*-lft-identityN/A
exp-prodN/A
lift-/.f32N/A
frac-2negN/A
distribute-frac-neg2N/A
pow-negN/A
lower-/.f32N/A
lower-pow.f32N/A
exp-1-eN/A
lower-E.f32N/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Taylor expanded in u around 0
rec-expN/A
log-EN/A
distribute-lft-neg-inN/A
lower-exp.f32N/A
distribute-lft-neg-inN/A
associate-*r/N/A
metadata-evalN/A
distribute-neg-fracN/A
metadata-evalN/A
lower-/.f3296.4
Applied rewrites96.4%
Final simplification96.4%
(FPCore (u v)
:precision binary32
(+
(*
(log
(+
(*
(/ 1.0 (- 1.0 (/ (- -2.0 (/ (+ (/ 1.3333333333333333 v) 2.0) v)) v)))
(- 1.0 u))
u))
v)
1.0))
float code(float u, float v) {
return (logf((((1.0f / (1.0f - ((-2.0f - (((1.3333333333333333f / v) + 2.0f) / v)) / v))) * (1.0f - u)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((((1.0e0 / (1.0e0 - (((-2.0e0) - (((1.3333333333333333e0 / v) + 2.0e0) / v)) / v))) * (1.0e0 - u)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32(Float32(Float32(1.0) / Float32(Float32(1.0) - Float32(Float32(Float32(-2.0) - Float32(Float32(Float32(Float32(1.3333333333333333) / v) + Float32(2.0)) / v)) / v))) * Float32(Float32(1.0) - u)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((((single(1.0) / (single(1.0) - ((single(-2.0) - (((single(1.3333333333333333) / v) + single(2.0)) / v)) / v))) * (single(1.0) - u)) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(\frac{1}{1 - \frac{-2 - \frac{\frac{1.3333333333333333}{v} + 2}{v}}{v}} \cdot \left(1 - u\right) + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
*-lft-identityN/A
exp-prodN/A
lift-/.f32N/A
frac-2negN/A
distribute-frac-neg2N/A
pow-negN/A
lower-/.f32N/A
lower-pow.f32N/A
exp-1-eN/A
lower-E.f32N/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Taylor expanded in v around -inf
mul-1-negN/A
unsub-negN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites94.7%
Final simplification94.7%
(FPCore (u v) :precision binary32 (+ (* (log (+ (* (/ 1.0 (+ (/ (+ (/ 2.0 v) 2.0) v) 1.0)) (- u)) u)) v) 1.0))
float code(float u, float v) {
return (logf((((1.0f / ((((2.0f / v) + 2.0f) / v) + 1.0f)) * -u) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((((1.0e0 / ((((2.0e0 / v) + 2.0e0) / v) + 1.0e0)) * -u) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32(Float32(Float32(1.0) / Float32(Float32(Float32(Float32(Float32(2.0) / v) + Float32(2.0)) / v) + Float32(1.0))) * Float32(-u)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((((single(1.0) / ((((single(2.0) / v) + single(2.0)) / v) + single(1.0))) * -u) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(\frac{1}{\frac{\frac{2}{v} + 2}{v} + 1} \cdot \left(-u\right) + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
*-lft-identityN/A
exp-prodN/A
lift-/.f32N/A
frac-2negN/A
distribute-frac-neg2N/A
pow-negN/A
lower-/.f32N/A
lower-pow.f32N/A
exp-1-eN/A
lower-E.f32N/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Taylor expanded in v around -inf
+-commutativeN/A
lower-+.f32N/A
Applied rewrites93.0%
Taylor expanded in u around inf
mul-1-negN/A
lower-neg.f3293.3
Applied rewrites93.3%
Final simplification93.3%
(FPCore (u v) :precision binary32 (+ (* (log (+ (/ (- 1.0 u) (+ (/ (+ (/ 2.0 v) 2.0) v) 1.0)) u)) v) 1.0))
float code(float u, float v) {
return (logf((((1.0f - u) / ((((2.0f / v) + 2.0f) / v) + 1.0f)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((((1.0e0 - u) / ((((2.0e0 / v) + 2.0e0) / v) + 1.0e0)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32(Float32(Float32(1.0) - u) / Float32(Float32(Float32(Float32(Float32(2.0) / v) + Float32(2.0)) / v) + Float32(1.0))) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((((single(1.0) - u) / ((((single(2.0) / v) + single(2.0)) / v) + single(1.0))) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(\frac{1 - u}{\frac{\frac{2}{v} + 2}{v} + 1} + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
*-lft-identityN/A
exp-prodN/A
lift-/.f32N/A
frac-2negN/A
distribute-frac-neg2N/A
pow-negN/A
lower-/.f32N/A
lower-pow.f32N/A
exp-1-eN/A
lower-E.f32N/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Taylor expanded in v around -inf
+-commutativeN/A
lower-+.f32N/A
Applied rewrites93.0%
lift-+.f32N/A
+-commutativeN/A
lower-+.f3293.0
Applied rewrites93.0%
(FPCore (u v) :precision binary32 (+ (* (log (+ (* (/ 1.0 (+ (/ 2.0 (* v v)) 1.0)) (- 1.0 u)) u)) v) 1.0))
float code(float u, float v) {
return (logf((((1.0f / ((2.0f / (v * v)) + 1.0f)) * (1.0f - u)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((((1.0e0 / ((2.0e0 / (v * v)) + 1.0e0)) * (1.0e0 - u)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32(Float32(Float32(1.0) / Float32(Float32(Float32(2.0) / Float32(v * v)) + Float32(1.0))) * Float32(Float32(1.0) - u)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((((single(1.0) / ((single(2.0) / (v * v)) + single(1.0))) * (single(1.0) - u)) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(\frac{1}{\frac{2}{v \cdot v} + 1} \cdot \left(1 - u\right) + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
*-lft-identityN/A
exp-prodN/A
lift-/.f32N/A
frac-2negN/A
distribute-frac-neg2N/A
pow-negN/A
lower-/.f32N/A
lower-pow.f32N/A
exp-1-eN/A
lower-E.f32N/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Taylor expanded in v around -inf
+-commutativeN/A
lower-+.f32N/A
Applied rewrites93.0%
Taylor expanded in v around 0
Applied rewrites91.1%
Final simplification91.1%
(FPCore (u v) :precision binary32 (+ (* (log (+ (* (/ 1.0 (+ (/ 2.0 v) 1.0)) (- 1.0 u)) u)) v) 1.0))
float code(float u, float v) {
return (logf((((1.0f / ((2.0f / v) + 1.0f)) * (1.0f - u)) + u)) * v) + 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = (log((((1.0e0 / ((2.0e0 / v) + 1.0e0)) * (1.0e0 - u)) + u)) * v) + 1.0e0
end function
function code(u, v) return Float32(Float32(log(Float32(Float32(Float32(Float32(1.0) / Float32(Float32(Float32(2.0) / v) + Float32(1.0))) * Float32(Float32(1.0) - u)) + u)) * v) + Float32(1.0)) end
function tmp = code(u, v) tmp = (log((((single(1.0) / ((single(2.0) / v) + single(1.0))) * (single(1.0) - u)) + u)) * v) + single(1.0); end
\begin{array}{l}
\\
\log \left(\frac{1}{\frac{2}{v} + 1} \cdot \left(1 - u\right) + u\right) \cdot v + 1
\end{array}
Initial program 99.5%
lift-exp.f32N/A
*-lft-identityN/A
exp-prodN/A
lift-/.f32N/A
frac-2negN/A
distribute-frac-neg2N/A
pow-negN/A
lower-/.f32N/A
lower-pow.f32N/A
exp-1-eN/A
lower-E.f32N/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
Taylor expanded in v around inf
+-commutativeN/A
log-EN/A
lower-+.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f3289.9
Applied rewrites89.9%
Final simplification89.9%
(FPCore (u v) :precision binary32 1.0)
float code(float u, float v) {
return 1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = 1.0e0
end function
function code(u, v) return Float32(1.0) end
function tmp = code(u, v) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 99.5%
Taylor expanded in v around 0
Applied rewrites85.5%
(FPCore (u v) :precision binary32 -1.0)
float code(float u, float v) {
return -1.0f;
}
real(4) function code(u, v)
real(4), intent (in) :: u
real(4), intent (in) :: v
code = -1.0e0
end function
function code(u, v) return Float32(-1.0) end
function tmp = code(u, v) tmp = single(-1.0); end
\begin{array}{l}
\\
-1
\end{array}
Initial program 99.5%
Taylor expanded in u around 0
Applied rewrites5.8%
herbie shell --seed 2024243
(FPCore (u v)
:name "HairBSDF, sample_f, cosTheta"
:precision binary32
:pre (and (and (<= 1e-5 u) (<= u 1.0)) (and (<= 0.0 v) (<= v 109.746574)))
(+ 1.0 (* v (log (+ u (* (- 1.0 u) (exp (/ -2.0 v))))))))